From: "Omar Polo" <op@omarpolo.com>
Subject: Re: delta cache improvement for got-index-pack
To: Stefan Sperling <stsp@stsp.name>
Cc: gameoftrees@openbsd.org
Date: Wed, 25 Feb 2026 07:51:29 +0100

Stefan Sperling <stsp@stsp.name> wrote:
> Cloning ports.git with 'got clone' is quite slow, more than 10 minutes.
> I have been looking for ways to improve this. I have found a way to speed
> up indexing of the pack file, specifically the "resolving deltas" step.
>  
> The diff below increases delta cache hit rate during got-index-pack from
> 60% to 90% when indexing a full pack of the ports.git repository.
> In my test case, where I use a ports.git repository with history between
> 1995 and 2016, the time taken to index the full pack file is reduced from
> 90 seconds to 30 seconds.
>  
> As a bonus, memory usage decreases on average since we keep fewer deltas
> in cache than before. Set an uppper limit on cache entries to keep memory
> usage within reasonable limits. The maximum is now about 1.2GB in the
> contrived case where all deltas and fulltexts are of the maximum size
> allowed. In practice we hover at around 500 MB with ports.git.
> The previous theoretical maximum was about 2GB.
> 
> ok?

why not.  okay op@

> 
> diff /home/stsp/src/got
> path + /home/stsp/src/got
> commit - d07cf78033793607c02ab0e8bcb66de1f4a02a6f
> blob - f4573ec7892464be6d8b1d3a6baf3decade28e4c